languagetool-org/languagetool · error · UnsupportedPatternRuleException

Term/POS combination not supported yet: + patternToken

Error message

Term/POS combination not supported yet: + patternToken

What it means

Search-index guard in makeQuery: the pattern element's combination of literal term and POS tag cannot be expressed as a Lucene query for the index; the specific token is included in the message.

Source

Thrown at languagetool-wikipedia/src/main/java/org/languagetool/dev/index/PatternRuleQueryBuilder.java:109

  private BooleanClause makeQuery(PatternToken patternToken) throws UnsupportedPatternRuleException {
    checkUnsupportedElement(patternToken);

    String termStr = patternToken.getString();
    String pos = patternToken.getPOStag();

    BooleanClause termQuery = getTermQueryOrNull(patternToken, termStr);
    BooleanClause posQuery = getPosQueryOrNull(patternToken, pos);

    if (termQuery != null && posQuery != null) {
      // if both term and POS are set, we create a query where both are at the same position
      if (mustOccur(termQuery) && mustOccur(posQuery)) {
        SpanQuery spanQueryForTerm = asSpanQuery(termQuery);
        SpanQuery spanQueryForPos = asSpanQuery(posQuery);
        SpanQuery[] spanClauses = {spanQueryForTerm, spanQueryForPos};
        return new BooleanClause(new SpanNearQuery(spanClauses, 0, false), BooleanClause.Occur.MUST);
      } else {
        // should not happen, we always use Occur.MUST:
        throw new UnsupportedPatternRuleException("Term/POS combination not supported yet: " + patternToken);
      }
    
    } else if (termQuery != null) {
      return termQuery;

    } else if (posQuery != null) {
      return posQuery;
    }
    throw new UnsupportedPatternRuleException("Neither POS tag nor term set for element: " + patternToken);
  }

  private SpanQuery asSpanQuery(BooleanClause query) {
    if (query.getQuery() instanceof MultiTermQuery) {
      return new SpanMultiTermQueryWrapper<>((MultiTermQuery) query.getQuery());
    } else {
      Set<Term> terms = new HashSet<>();
      try {
        indexSearcher.createWeight(query.getQuery(), false).extractTerms(terms);

View on GitHub (pinned to 2e990059ce)

Solutions

1. Use only a term or only a POS tag on that element
2. Relax the token (e.g. drop inflection or chunk constraints)
3. Skip the rule during index-based search

When it happens

Trigger: Thrown at languagetool-wikipedia/src/main/java/org/languagetool/dev/index/PatternRuleQueryBuilder.java:109 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of languagetool-org/languagetool@2e990059ce (2026-09-06). Data as JSON: /api/errors/998f348ea6b7cfda. Report an issue: GitHub.